Should I use Phosfree? Does it clog filters?

Hi everyone

For years I have had this problem where I have to clean my cartridge filters every month or 2. Finally, due to some suggestions on these forums, I went 5 months before it needed to be cleaned. Sweet! In fact the pressure rinsed only 1 mm the entire time (17 to 18). Than I went to Leslies Pools to check my pool chemistry and they said my phosphates are sky high (2500). They told me to put in a whole bottle of phosfree. Well a week later my pressure rises very quick all the way to 26. Now my filters need to be cleaned. Now granted I add a capful of phosfree weekly, but I heard that phosfree actually clogs you filters and causes the pressure to rise. And some have said it isn't even necessary to use as one can avoid algae without it.

So my question is what is your opinion on phosfree?